Douglas Bigelow, 49; Web Security Chief for America Online

Douglas Bigelow, 49, a pioneer in Internet protection who fought e-mail spam, computer viruses, identity theft and online pornography as the head of security for the world’s largest Internet service provider, died of pancreatic cancer Dec. 24 at his home in Vienna, Va.

In 1995, he became America Online’s vice president of operations security and the company’s first employee responsible for protecting both customer and corporate data. Ten years later, he managed a department of more than 100 people and investigated thousands of security issues a year, said Matt Korn, an executive vice president at AOL.

Bigelow was born in Manchester, Conn., grew up in nearby Glastonbury and graduated from Wesleyan University. After earning a master’s degree from Ohio State University in computer science in 1980, he worked at Wesleyan before joining AOL. He helped connect Wesleyan and other schools to Bitnet, one of the many computer networks that preceded what is now known as the Internet.